228 CALIFORNIA ACADEMY OF SCIENCES. 



Pleopods in the male rather small. Telsou narrow, channelled above, 

 somewhat constricted behind the base, the sides gently rounded and 

 tapering from near the middle to the narrowly rounded tip; the sides and 

 tip armed with spines; three large spines on each margin of the slightly 

 widened base, behind which is a short interval at the constriction devoid 

 of spines, beyond which the margin is closely set with spines to the tip; 

 two somewhat larger spines at the distal end between which are three very 

 short spines and a pair of plumose setaa. Inner ramus of the uropods 

 narrow, scarcely expanded at the base, distally rounded, slightly exceed- 

 ing the telson, setose on both margins and furnished with strong spines 

 along the inner side. Outer ramus larger and much wider than the inner, 

 the outer margin armed with (10-14) spines which begin about the anterior 

 fourth of its length and extend, gradually increasing in size, to the articu- 

 lated portion, where the ramus is somewhat constricted and beyond which 

 the margin is furnished with plumose setae. 



Length 11 mm. 



The color of several specimens preserved in formalin is white or a very 

 pale pink. Pigment is scarce but on the posterior marsupial lamella of 

 the females there is a pair of large, irregularly branched pigment spots, 

 the two anterior lamellae having each a single pigment spot. 



Several specimens caught in a tow net at San Diego, 

 Calif., October 15, 1898. A single female specimen 

 taken at Santa Catalina Island, August 3, 1893. The 

 marsupial pouch contained young embryos in speci- 

 mens from both these localities. 



Collection University of California. 



This species resembles Siriella Thompsonii Milne- 

 Edwards, but may readily be distinguished by the two- 

 jointed propodi of the thoracic legs. 



Family EUPHAUSIIDvE. 



Carapace rather small, not calcareous. Branchiae arborescent, situated 

 on the coxae of the thoracic legs. Thoracic legs generally similar in form, 

 the hinder pairs somewhat rudimentary. No marsupial lamellae. Pereo- 

 pods well developed and natatory in both sexes. Inner ramus of the 

 uropods devoid of an auditory organ. Telson long and slender, with two 

 long, spiniform appendages attached in front of the tip. 



